I have an old one of those (the form factor was different) and I recall it running on bus power.
Anyway.
It was pretty useful for me- my version could click too, so you had multiple “gestures” you could map:
-click
-press turn right
-press turn left
-turn right
-turn left
So there was more utility than you’d think. I’ll have to dig that out again…

They’ve made a USB version, very similar in most respects, for some years now. Always a trifle too expensive for me to justify; but I’ve always kind of wanted one.

What I’ll be interested to see is how this device exposes itself to the host system. I’d assume that it shows up as BT HID, with either nonstandard keycodes or some nonstandard data carried over BT HID for convenience (both USB and BT HID offer a fairly convenient mechanism to bundle up vendor-specific data, so long as you don’t need hugely aggressive data rates, and they have fairly robust drivers that do much of the work for you on most OSes, so they are commonly used for slightly odd input devices); in which case making it work with non-OSX should be fairly doable.

If they rolled their own godforsaken excuse for a protocol, that would be less good.

When I got the USB version many many years ago, for use in The Contraption, there was very little support for it. You could code your own python routines to it as long as you were willing to compile your own drivers, or load binaries from dodgy Internet sites. I did it for a while but then got tired of recompiling to fix bugs arising from routine OS patching; left it connected but did not use it.

After a while there started to be decent OS support for it as a volume control knob. Today it often works “out of the box” with various linux and windows versions - for volume control. I don’t have a current OS mac (this Mac beside me is an iLamp model) so I don’t know how well Griffin knobs are currently supported on Mac.

And obviously all the above is referencing the USB model, not the bluetooth one. They are both very well designed to fit the human hand and eye.

They’ve made a USB version, very similar in most respects, for some years now. Always a trifle too expensive for me to justify; but I’ve always kind of wanted one.

I’d go for Arduino based on ATmega32u4, LUFA stack for the USB protocol, some demo app that combines keyboard/mouse and serial port in one device. Use the serial port for programming what HID responses the device should do. Optionally use a userspace software for mapping the events to actions based on which app is foreground (for Windows, AutoHotKey does a perfect job; you can borrow the CapsLock key for a macro key, for example, that’s application-specific).

For sensors, an old VCR head is a good massive rotating thing with excellent bearings. Game console controllers can give those neat minijoysticks. Old laptops can provide touchpads that typically communicate over PS2 protocol and behave like mice; this signal can be decoded into HID events, either directly as a dumb mouse or interpreted and translated to e.g. control of sliders. Assemble any functionality you want.